linux-kernel - Re: [PATCH] thp: tail page refcounting fix #5

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Message-ID: <20110902011716.GE7761@one.firstfloor.org>
Date:	Fri, 2 Sep 2011 03:17:16 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Andrea Arcangeli <aarcange@...hat.com>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Michel Lespinasse <walken@...gle.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Hugh Dickins <hughd@...gle.com>,
	Johannes Weiner <jweiner@...hat.com>,
	Rik van Riel <riel@...hat.com>, Mel Gorman <mgorman@...e.de>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Shaohua Li <shaohua.li@...el.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: Re: [PATCH] thp: tail page refcounting fix #5

> Calling get_page/put_pages more times than necessary is never ideal, I
> imagine the biggest cost is the atomic_inc on the head page that

I've actually seen it in profile logs, but I hadn't realized it was redundant.

Have to see if it brings a benefit to hot users.

-Andi
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